code: def test_zeros():
      """Test on an image of all zeros"""
      workspace, module = make_workspace(
          numpy.zeros((10, 20, 3)),
          [cellprofiler.modules.unmixcolors.CHOICE_HEMATOXYLIN],
      )
      module.run(workspace)
      image = workspace.image_set.get_image(output_image_name(0))
      #
      # All zeros in brightfield should be all 1 in stain
      #
      numpy.testing.assert_almost_equal(image.pixel_data, 1, 2)
  
file_path: CellProfiler/tests/frontend/modules/test_unmixcolors.py
imports: import numpy
  import six.moves
  import cellprofiler_core.image
  import cellprofiler_core.measurement
  import cellprofiler.modules.unmixcolors
  import cellprofiler_core.object
  import cellprofiler_core.pipeline
  import cellprofiler_core.workspace
  import tests.frontend.modules
label_desc: Use image node_id 5 for calling a global function with example usage: test_zeros() without return types